1. Field of the Invention
The present invention relates generally to a liquid crystal display device utilizing in-plane switching mode, and more particularly to such a liquid crystal display device having a storage capacitor.
2. Related Art
Liquid crystal displays have been burdened by limited viewing angles for many years. Many researchers in the art have invested huge amounts of time and effort in trying to find possible solutions for this shortcoming. One solution was developed by Masahito Ohe et al., and is disclosed in U.S. Pat. No. 5,600,464. This is the so-called liquid crystal display device with in-plane switching (IPS) mode.
In order for an IPS mode liquid crystal display device to have a higher aperture ratio, Seo et al. developed an “In-Plane Switching Mode Liquid Crystal Display Device Having a High Aperture Ratio,” which is disclosed in U.S. Pat. No. 6,628,362 (the '362 patent). In particular, a storage capacitor having a reduced effective area for enlarging the aperture ratio is disclosed. Referring to FIG. 2B of the '362 patent, a circular mark 125 represents a group of electrodes, which are overlapped to form two storage capacitors. As shown, one storage capacitor is formed by a common electrode 109 and a data electrode 108, while the other storage capacitor is formed by the data electrode 108 and a gate electrode 101. However, due to the existence of unexpected coupling effects, such as a capacitive coupling effect, in a liquid crystal display device, especially in an IPS mode liquid crystal display device, the voltage of a pixel electrode is affected by data signals carried on a data signal line driving other pixels. This significantly reduces the quality of images displayed on the liquid crystal display device.